The enormous power of ocean waves has been known for millennia. In recent decades, as global demand for energy has increased and energy supplies have suffered bottlenecks, interest has grown in harnessing that power and converting it into usable energy.
Ocean wave energy is close to free after initial capital costs are paid, making it an excellent candidate for low-cost power generation. Unlike photovoltaic cells which normally wear out and require complete replacement within a decade or two, the mechanical equipment of an ocean wave energy generator can be made to have an extremely long life span, as mechanical equipment of this type can be made to last for many millions of cycle of use. Unlike fossil fuels, no fuel source is burned once: no fuel is needed at all.
The amount of electrical energy required is persistently increasing across time. According to Roger Kranenburg (energy executive), the US share of energy used to generate electrical energy has increased four fold in two generations, as shown in FIG. 10. In 1940, only 10% of US energy consumption was electricity, but by 1970, this figure had more than doubled, and it continues to double to approximately 40% by the present time, with no sign of leveling off. This pattern is repeated in developing nations such as the nations of Central America. Obviously, acquisition of energy generation capacity which has only capital costs and almost no maintenance costs and no fuel costs whatsoever would be every advantageous.
Wave energy has another advantage. Most of the Earth's population lives quite close to an ocean. Over two thirds of the human population lives within 400 kilometers of a coast, in fact, over one half live within 200 kilometers (˜120 miles) of a coast. This distance is well within the practical distance for electricity transmission (electricity generation over long distances still suffers from some problems to this day). This statistical trend holds true for every one of the populated continents except Africa, and even in Africa demographic changes are causing the population to trend towards the coasts. The result is that over one half of the world's population lives on only 10% of the land area of the planet (roughly 3% of the total area of the planet), and that tiny percentage is the strip of land by the ocean. FIG. 9 shows the overall distribution of population of the world, the United States, and Latin America. It is worth noting that Latin America is an extremely good candidate for ocean wave energy as Latin America has fully three quarters of the population of the region living on a coast. FIG. 8 is more relevant to the United States, and shows the major population concentrations of the western half of the nation. Four inland cities have a combined population of approximately 10 million or less while five major urban areas (often composed of more than one major city each) have a combined population roughly three times as great: approximately 30 million people. The three largest western US urban areas are on the West Coast, along with the several “smaller” major cities. Yet informal surveys by the applicant reveal excellent spots for ocean wave generation facilities of the type taught by the invention are available even in the middle of the these heavily built up urban areas. A number of schemes have been proposed for generating energy from waves. Almost invariably, these schemes seek to provide large and complex structures in the tidal zone of the ocean, presumably at great cost and effort. However, the locations most in need of wave energy generation facilities are not normally wealthy. In addition, the requirements for complex mechanisms require that the equipment be imported from distant locations at further expense. Worse, the necessity to import expensive equipment may make such installations impossible for regions which have unfavorable balances of trade. A search in the collection of patents of the United States reveals a number of examples of these schemes.
U.S. Pat. No. 6,956,300 issued Oct. 18, 2005 to Gizara is typical: it envisions placing a railroad track on the floor of the body of water, then placing a gimbal-mounted hydroelectric generator on a carriage running on the tracks.
U.S. Pat. No. 6,781,253 issued Aug. 24, 2004 to Newman teaches a system in which large pipes, sleeves and pistons are planted in the wave zone of the ocean floor.
U.S. Pat. No. 6,700,217 issued Mar. 2, 2004 North et al. is another example of the type of system which requires a great deal of equipment be placed on the ocean floor, in this case pressure sensitive devices.
U.S. Pat. No. 6,647,716 issued Nov. 18, 2003 to Boyd teaches a network of devices floating in the wave zone of the ocean equipped with floats, rams, and other equipment.
U.S. Pat. No. 6,133,644 issued Oct. 17, 2000 to Smith et al. teaches a floating paddlewheel device located off shore.
U.S. Pat. No. 5,789,826 issued Aug. 4, 1998 to Kumbatovic teaches a crane located on a fixed point on shore and holding a large conveyor belt paddlewheel arrangement into surf, while U.S. Pat. No. 5,311,064 issued May 10, 1994 to the same inventor teaches a simpler paddlewheel arrangement and a larger, two legged crane.
U.S. Pat. No. 5,359,229 issued Oct. 25, 1994 to Youngblood teaches a massively plural array of floats with counterweights, anchored off shore.
U.S. Pat. No. 4,781,023 issued Nov. 1, 1988 to Gordon teaches a raft and a fixed mooring: relative motion of the raft, anchored off shore, allows energy generation.
U.S. Pat. No. 4,718,231 issued Jan. 12, 1988 to Vides teaches a large piece of civil engineering with multiple floats and support arms.
U.S. Pat. No. 4,672,222 issued Jun. 9, 1987 to Ames teaches a multiplicity of tripod energy absorbers placed well off shore in a wave zone.
U.S. Pat. No. 4,345,434 issued Aug. 24, 1982 to Nedyalkov teaches a group of containers which are anchored well off shore and motion of water between the containers provides power.
A few systems at least attempt to teach less complex methods and apparatus.
U.S. Pat. No. 6,711,897 issued Mar. 30, 2004 to Lee at least teaches a relatively low cost system having no requirement for ocean floor equipment, but requires either extended float arms capable of reaching distance from the shoreline, or else requires a pier or dock in the wave zone, as shown in the diagrams of the patent.
U.S. Pat. No. 6,247,308 issued Jun. 19, 2001 to Solell teaches a plurality of floats hooked to a single rotary shaft, but the floats appear to float freely in an off-shore location.
U.S. Pat. No. 5,105,094 issued Apr. 14, 1992 to Parker teaches a device of large scale having a large pipeline off shore, with multiple water inlet positions feeding a single piston located closer to shore.
One disadvantage of most of these schemes is that they require that large items of machinery work properly in the marine environment (under ocean water) for many cycles of use. But the prior art schemes of putting equipment on the sea bed have disadvantages. For example, the underwater environment is an extremely arduous environment in a number of ways. Sea water, which contains various minerals and their salts, is corrosive by itself. The ocean is continuously in motion, and particularly during storms, even the largest equipment can be destroyed by the enormous forces generated by masses of water in motion. Sea life tends to grow onto and encrust any man-made object left under water for very long. Generally, it would be advantageous if the energy generation machinery could be place *on land*, rather than in the ocean surf, and yet still generate energy from ocean waves.
None of these devices teaches that the land itself may be a part of the power generation structure. None of these devices teach equipment which may be manufactured on-site or in local areas lacking a “high tech” industrial base. None teach pneumatic methods of transducing wave motion into electrical energy. These devices are sophisticated, expensive, high maintenance apparatus, which require highly trained specialists to operate.
It would be preferable to provide low maintenance apparatus which may convert ocean wave energy to electrical energy.
It would be preferable to provide apparatus which does not require highly trained specialists to operate.
It would be preferable to provide low cost, easy to manufacture methods which may be susceptible to local production by relatively simple methods.
It would further be preferable to provide a structure using the coastline configuration itself to generate electrical energy.